There are two versions of the Abena Abri-Form X-Plus level 4. There is a cloth backed version (usually marketed as "premium") and there is a plastic backed version (usually marketed as "comfort" or "classic"). So if you want plastic backed, the only reason to get the cloth backed version would be if you want a smaller size (for cloth backed there is x-small, small, medium and x-large, and for plastic there is medium, large and x-large). Cloth backed diapers are less crinkly so it helps for wearing in public, but they are prone to leaking through the wings because the only material in the wings is the cloth backing which isn't waterproof. Plastic backed diapers are more crinkly which many AB/DL's like (but isn't good for wearing in public because it helps give away the fact that you're diapered). They are also less prone to leaking because the wings are made of the waterproof plastic backing, and they have better odor control. The major reason other than the crinkling that most companies switched to cloth backed is that plastic backed diapers aren't breathable (not a huge issue in my opinion). So, if you're mainly wearing at home, I would recommend going plastic backed (if you wear say cargo shorts or jeans over your diapers the crinkling will be mostly covered up, so that helps for wearing plastic backed in public). Cloth backed is good for wearing if you wear mostly in public, or if it's really hot. My personal preference is plastic backed. Also, you were correct in hearing that Abena is very good. They are very thick, very absorbent, and very soft and comfortable. I'll provide you with a link to what I think is the best place to buy Abena, XP Medical. If you buy a case, you get free shipping (I would recommend that because you said you'd just want 3 bags, as a case of Abena's is the same as 3 bags). Their shipping is also discreet so there are no labels or markings leading anyone to believe that there are diapers inside the shipping box. Here's a link to the plastic Abena's.
http://xpmedical.com/abriform.html
If you're unsure what size to get, here's a link to a page about how to size your diapers and other ABDL clothing:
http://www.adisc.org/forum/showthread.php/83311-Taking-Measurements-for-Clothing
Also, if you decided you want cloth backed, here is a link to Abena Delta Form diapers. They are basically the exact same as the Abri-Form cloth backed, except for the fact that they aren't available in absorbency level 4, and the come in colors instead of white (medium is blue, large is green). The level 3 has almost as much absorbency as the Abri-Form Level 4, so it is well worth it for the lower price. Also, you may hear in other places that these are plastic backed but they are indeed cloth backed (they used to be plastic backed a few years ago).
http://xpmedical.com/deltaform.html
I would recommend getting a case of Abri-Form plastic backed as well as a sample pack of Delta Form, but if you want completely free shipping just get the case of Abri-Forms. I would also recommend browsing their site, as there are many other good diapers they sell. Here are some other good places to buy diapers:
http://www.northshorecare.com/
https://snuggiesdiapers.com/en/
http://bambinodiapers.com/
If you want reviews of some of these diapers, check them out in ADISC's diaper review section:
http://www.adisc.org/forum/forumdisplay.php/53-Diaper-Reviews
I hope I could be of help, and good luck to you in starting out with AB/DL!
Thanks!
Luvtowearpampers